Method and apparatus for rotating an image on a display

Abstract

A method and apparatus utilizes a three dimensional rendering engine to rotate an image based on user selected or otherwise determined screen orientation. A vertex coordinate transformation is defined for a rotated destination image. The source image is used as a texture for texture mapping during rendering operation to produce rotated image. In one embodiment, a separate set of software instructions is used for each orientation mode. Accordingly, a non-pixel by pixel based 3D rotation may be carried out using a 3D rendering engine to avoid a single parameter based seriatim pixel by pixel based orientation.

1. A method for displaying images on a display screen, said method comprising:
 receiving a display screen orientation angle; 
 defining a source image as a texture; 
 generating geometric primitives for a three dimensional (3D) rendering engine, said geometric primitives corresponding to a rotated display screen image based upon the display screen orientation angle and the source image; 
 mapping the texture onto the generated geometric primitives; and 
 outputting the rotated display screen image based on the generated geometric primitives. 
 
     
     
       2. The method of  claim 1  wherein said mapping is performed by the three dimensional (3D) rendering engine. 
     
     
       3. The method of  claim 1  wherein said display screen orientation angle is received via a rotation detection sensor. 
     
     
       4. The method of  claim 1  wherein said display screen orientation angle is received via a user interface. 
     
     
       5. The method of  claim 1 , wherein generating the geometric primitives for the 3D rendering engine comprises:
 calculating vertices of a target area based on the display screen orientation angle. 
 
     
     
       6. The method of  claim 5 , wherein calculating the vertices comprises calculating the vertices to tessellate the display screen image. 
     
     
       7. The method of  claim 5 , wherein calculating the vertices comprises associating each vertex of the generated geographic primitives with a corresponding point of the display screen image. 
     
     
       8. The method of  claim 5 , wherein further comprising storing the source image in an off-screen memory. 
     
     
       9. The method of  claim 8 , further comprising:
 mapping the source image from the off-screen memory based on calculating the vertices. 
 
     
     
       10. A non-transitory computer-readable medium storing instructions for causing a computing device to:
 receive a display screen orientation angle; 
 define a source image as a texture; 
 generate geometric primitives for a three dimensional (3D) rendering engine, said geometric primitives corresponding to a rotated display screen image based upon the display screen orientation angle and the source image; 
 map the texture onto the generated geometric primitives; and 
 output the rotated display screen image based on the generated geometric primitives. 
 
     
     
       11. The computer-readable medium of  claim 10  wherein the three dimensional (3D) rendering engine maps the texture onto the generated geometric primitives. 
     
     
       12. The computer-readable medium of  claim 10  wherein said display screen orientation angle is received via a rotation detection sensor. 
     
     
       13. The computer-readable medium of  claim 10  wherein said display screen orientation angle is received via a user interface. 
     
     
       14. The computer-readable medium of  claim 10 , wherein the instructions further cause the computing device to:
 calculate vertices of a target area based on the display screen orientation angle. 
 
     
     
       15. The computer-readable medium of  claim 14 , wherein the instructions further cause the computing device to:
 calculate the vertices to tessellate the display screen image. 
 
     
     
       16. The computer-readable medium of  claim 15 , wherein the instructions further cause the computing device to:
 calculate the vertices by associating each vertex of the generated geographic primitives with a corresponding point of the display screen image. 
 
     
     
       17. The computer-readable medium of  claim 15 , wherein the instructions further cause the computing device to:
 store the source image in an off-screen memory. 
 
     
     
       18. The computer-readable medium of  claim 17 , wherein the instructions further cause the computing device to:
 map the source image from the off-screen memory based on calculating the vertices. 
 
     
     
       19. An apparatus for displaying images on a display screen, comprising:
 a first processor configured to receive a display screen orientation angle; 
 wherein said first processor is also configured to define a source image as a texture; 
 wherein said first processor is also configured to generate geometric primitives for a second processor, said geometric primitives corresponding to a rotated display screen image based upon the display screen orientation angle and the source image; 
 wherein said second processor configured to map the texture onto the generated geometric primitives; and 
 wherein at least one of said first processor said second processor are configured to output the rotated display screen image based on the generated geometric primitives. 
 
     
     
       20. The apparatus of  claim 19  wherein said second processor is a three dimensional (3D) rendering engine. 
     
     
       21. The apparatus of  claim 19  wherein said display screen orientation angle is received via a rotation detection sensor. 
     
     
       22. The apparatus of  claim 19  wherein said display screen orientation angle is received via a user interface. 
     
     
       23. The apparatus of  claim 19 , wherein the first processor is configured to generate the geometric primitives for the 3D rendering engine by calculating vertices of a target area based on the display screen orientation angle. 
     
     
       24. The apparatus of  claim 23 , wherein the first processor is configured to calculate the vertices to tessellate the display screen image. 
     
     
       25. The apparatus of  claim 23 , wherein the first processor is configured to calculate the vertices via associating each vertex of the generated geographic primitives with a corresponding point of the display screen image. 
     
     
       26. The apparatus of  claim 23 , wherein the first processor is further configured to:
 store the source image in an off-screen memory. 
 
     
     
       27. The apparatus of  claim 26 , wherein the first processor is further configured to:
 map the source image from the off-screen memory based on the calculated vertices. 
 
     
     
       28. An apparatus for displaying images of an application on a display, comprising:
 means for receiving a display screen orientation angle; 
 means for defining a source image as a texture; 
 means for generating geometric primitives for a three dimensional (3D) rendering engine, said geometric primitives corresponding to a rotated display screen image based upon the display screen orientation angle and the source image; 
 means for mapping the texture onto the generated geometric primitives; and 
 means for outputting the rotated display screen image based on the generated geometric primitives. 
 
     
     
       29. The apparatus of  claim 28  wherein the means for mapping is performed by the three dimensional (3D) rendering engine. 
     
     
       30. The apparatus of  claim 28  wherein said display screen orientation angle is received via a rotation detection means. 
     
     
       31. The apparatus of  claim 28  wherein said display screen orientation angle is received via a user interface. 
     
     
       32. The apparatus of  claim 28 , wherein the means for generating the geometric primitives further comprises means for calculating vertices of a target area based on the display screen orientation angle. 
     
     
       33. The apparatus of  claim 32 , wherein the means for calculating the vertices tessellates the display screen image. 
     
     
       34. The apparatus of  claim 32 , wherein the means for calculating the vertices associate each vertex of the generated geographic primitives with a corresponding point of the display screen image. 
     
     
       35. The apparatus of  claim 32 , further comprising means for storing the source image in an off-screen memory. 
     
     
       36. The apparatus of  claim 35 , wherein the means for generating the geometric primitives maps the source image from the off-screen memory based on the means for calculating the vertices.